1. Field of the Invention
This invention relates to a semiconductor device applied to a light-emitting device, an electronic device, etc. and a process for producing the semiconductor device.
2. Related Background Art
Heretofore, semiconductor devices of III-V group compounds such as GaAs, etc. have been formed by epitaxial growth on a substrate of GaAs monocrystal, but the epitaxial growth on such a monocrystalline substrate has been limited by materials of the monocrystalline substrate and it has been impossible to obtain a larger area and a three-dimensional integration. On the other hand, need for arrays of larger area or three-dimensional optical integrated circuits for use in light parallel processing, etc. are increasing and growth technique of monocrystal on an amorphous substrate is in keen demand. As one of the art of monocrystal growth on an amorphous substrate, a selective nucleation process is disclosed in Japanese Patent Application Laid-Open No. 63-237517, EP 0288166, etc.
The selective nucleation process is to apply a crystal growth treatment to a substrate having a free surface provided adjacent to an amorphous or polycrystalline non-nucleation surface having a low nucleation density and an amorphous or polycrystalline nucleation surface having a sufficiently small area for growth of crystals only from single nuclei and a larger nucleation density than that of the non-nucleation surface, thereby growing single monocrystals from the single nuclei.
FIG. 2 shows a semiconductor device obtained according to the selective nucleation process, wherein reference numeral 1 is a p side electrode, 2 is an insulating film, 3 is an n side electrode, 5 is a substrate, 6 is an n-type semiconductor, 7 is a p-type semiconductor and 8 is a seed crystal.
In the semiconductor device, an n side electrode 3 was overlapped with a p side electrode 1 through an insulating film 2 as shown in FIG. 2; conduction of the electrodes took place through pinholes of the insulating film or breaking of electrodes due to a level difference between the surface of substrate 5 and the device. Furthermore, there was a fluctuation in the resistance, resulting in fluctuations in the device characteristics, because one electrode was provided through one contact hole.